In the field of ultrasonic diagnostics, sector scans or linear scans of an object or body under examination may be achieved by using multi-element transducers which remain stationary with respect to body or object. The scan is produced by successively activating groups of elements so as to produce a series of ultrasonic beams which travel sequentially along the length of the transducer. In order to produce a beam which is focused in a focal plane positioned for optimum image information, it is necessary to pulse the various elements of a beam-producing group at slightly different times from one another. Likewise, the echoes received by the various elements of a group need to be delayed by corresponding amounts in order to produce a composite echo indication focused in the focal plane.
The production of the various delays involved in this type of scanning process is conventional and well known. The difficulty arises when large groups of elements must be rapidly switched to produce the travel of the beam. For example, in a scan having 128 separate beam positions, it would usually be necessary to switch a lens of 32 elements to different delay lines varying from 0 to about 800ns in typically less than 25 .mu.s in order to produce a complete scan for each frame of a TV picture.
Prior art switching systems capable of achieving these results have been highly complex, expensive, and have exhibited little versatility. Specifically, prior art devices have been unable to accommodate different types of transducer arrays and different types of scans without system modification. Also, most prior art devices have required many conductors between the transducer itself and the control unit containing the switching electronics.